Working version

server/cipherrwc.go

@@ -0,0 +1,52 @@
+package server
+
+import (
+	"bytes"
+	"io"
+)
+
+type Cipher interface {
+	Encrypt([]byte) []byte
+	Decrypt([]byte) []byte
+}
+
+type CipherReadWriteCloser struct {
+	crypt Cipher
+	conn  io.ReadWriteCloser
+	rest  *bytes.Buffer
+}
+
+func (c *CipherReadWriteCloser) Read(p []byte) (n int, err error) {
+	n, err = c.conn.Read(p)
+	copy(p, c.crypt.Decrypt(p[:n]))
+	return
+}
+
+func (c *CipherReadWriteCloser) Write(p []byte) (n int, err error) {
+	c.rest.Write(c.crypt.Encrypt(p))
+	newP := c.rest.Bytes()[:len(p)]
+	n, err = c.conn.Write(newP)
+	c.rest = bytes.NewBuffer(c.rest.Bytes()[n:])
+	return
+}
+
+func (c *CipherReadWriteCloser) Close() error {
+	var err1 error
+	if c.rest.Len() > 0 {
+		_, err1 = c.conn.Write(c.rest.Bytes())
+	}
+	err2 := c.conn.Close()
+
+	if err2 != nil {
+		return err2
+	}
+	return err1
+}
+
+func newCipherReadWriteCloser(conn io.ReadWriteCloser, crypt Cipher) io.ReadWriteCloser {
+	return &CipherReadWriteCloser{
+		conn:  conn,
+		crypt: crypt,
+		rest:  &bytes.Buffer{},
+	}
+}